Firefly: Out of Gas
I already posted mini reviews of most of the episodes, so I haven't been mentioning any of the episodes during my second rewatch, but man, this episode is one of the best things I've seen on TV, and better than a lot of the stuff I see in movies. Beautifully shot and edited, perfectly acted, and a very touching story told in a very unique way. Without a doubt my favorite episode of Firefly.